Protective sleeve for intake rack bars

ABSTRACT

A protective sleeve for use with metal intake racks used for screening debris from water intakes and other similar structures. The proactive sleeve may be made from a plastic material, such as HDPE, using an extrusion process. The sleeve is designed to snap into place over the metal blades of a bar rack, and to provide a positive and secure fit when in place. The protective sleeve thus provides the benefits of non-metallic intake racks to existing and future metal rack systems, without requiring replacement of existing metal racks.

This application is a continuation of U.S. patent application Ser. No.11/488,461, filed on Jul. 18, 2006, now U.S. Pat No. 7,919,003 which isassigned to the assignee of the present application and which claims thebenefit of U.S. Provisional Patent Application No. 60/700,682, filed onJul. 19, 2005, both of which patent applications are incorporated hereinby reference in their entirety.

FIELD OF THE INVENTION

This invention pertains generally to intake screens or racks that areused to prevent debris from entering into systems and facilities thatintake water from exposed above-ground water sources such as rivers,lakes, oceans and the like.

BACKGROUND OF THE INVENTION

Various systems and facilities intake large quantities of water fromvarious exposed natural and other above-ground water sources, such asrivers, lakes, oceans, reservoirs, irrigation and flood water canals,outdoor water parks, other water conveyance structures, and the like.Examples of such systems and facilities include hydroelectric plants,pulp and paper mills, steel mills, petro-chemical plants, municipalwater systems and waste water plants, nuclear and other energyfacilities that use the water for cooling or for other purposes, otherwater filtering or screening facilities or systems, etc. In all suchsystems it is important to screen naturally occurring debris found inthe exposed above-ground water source from the flow of water that istaken into and employed by the system or facility. Such debris mayinclude, for example, leaves, branches, and other portions of trees orother plants that have fallen into or grown in the water source, trash,and other debris that has been dumped or otherwise found its way intothe exposed above-ground water source, etc. Such debris could causesignificant damage to the system or facility obtaining water from theexposed above-ground water source if it were allowed to enter into thesystem or facility.

Various screening systems are known and used for preventing debris foundin exposed above-ground water sources from entering into the systems orfacilities described above. For example, fine mesh screening may be usedto exclude even small pieces of debris from such systems. Screeningsystems with larger openings may be used, either alone or in combinationwith finer screening, to prevent large debris from entering the systemor facility taking water from the exposed above-ground water source.Such larger opening screening systems may be used for preventing largedebris from reaching finer mesh screening positioned downstream from thelarger opening screening. Larger opening screening systems preferably donot dramatically adversely affect the water flow volume provided intothe facility or system through the screening system.

An exemplary screening system of this type is known as an intake racksystem or trash rack. Intake rack systems typically provide screeningusing a series of vertically oriented parallel blades or bars separatedby spacers and mounted on horizontally oriented rods. The spacingbetween the blades forming the intake rack is selected to screen debrisof the desired size from entering the water intake of the system orfacility that the trash rack is protecting, without significantlyreducing water flow into the water intake. Such intake racks may be madeof metallic or non-metallic materials. Intake racks of this type areavailable, for example, from Hydro Component Systems, LLC of Watertown,Wis.

In a typical application, intake racks of this type may be mountedupstream from the water intake of a hydroelectric or other plant, systemor facility that intakes water from a river or other similar exposedabove-ground water source. The elongated vertically oriented parallelblades forming the intake rack extend downward into the water to preventdebris floating at the water surface or in the water below the waterline from entering the system or facility. Various tools have beendeveloped for cleaning accumulated debris from intake racks and similarscreening systems. An example of such a tool is the Trash Rake Systemfor Clearing Intake Racks and the Like described in U.S. patentapplication Ser. No. 11/144,393 filed on Jun. 3, 2005, the disclosure ofwhich is incorporated herein by reference.

The leading edges of intake rack blades or bars, that is, the edges ofthe blades or bars that first contact water and debris flowing throughand against the intake rack, may be formed to have curved edges. Thishas several advantages. Curved leading edges facilitate better waterflow through the intake rack. Curved leading edges on the intake rackblades or bars also present less surface area over which a trash rake orother device must slide when cleaning debris from the intake rack. Lesssurface area means less friction, and less energy is thus required tomove the trash rake or other device across the intake rack during adebris cleaning operation.

As mentioned above, intake rack systems may be made of metallic ornon-metallic materials. For example, the vertical blades of an intakerack may be made of a durable plastic material, such as HDPE, or of ametal material, such as cold rolled steel.

Intake racks with metal rack blades or bars are the most commonly used.Such racks are very strong, and thus can withstand impacts from largedebris and other incidental contacts without being seriously damaged inmost cases. However, intake racks with rack blades made from metals,such as steel, also suffer from several significant limitations. Metalracks will rust unless treated with an epoxy coating. In cold weatherthe metal rack blades can conduct a freezing air temperature into thewater, causing ice to form on the rack blades. This ice acts as aninsulator, allowing the metal rack blades to conduct the coldtemperatures deeper into the water to continue the freezing process. Asice forms on the rack blades in this manner the flow of water throughthe intake rack is restricted.

Plastic intake racks do not suffer from many of the limitations of metalracks. Plastic racks do not rust or corrode, and thus are the preferredsolution for salt water applications in particular. Plastic racks don'ttransfer below freezing air temperatures into the water, and thusreduced water flow through the rack due to ice formation on the rackblades is eliminated. Marine growth, another potential cause of reducedwater flow through an intake rack, also is less prevalent in plasticintake rack systems. Marine growth does not stick to plastic as well asit does to coated steel intake racks.

Given the many advantages of plastic intake racks, plastic racks areoften a preferable solution. However, many facilities already have metalintake rack systems in place. To replace such installed metal racksystems with plastic racks would be an expensive undertaking.

What is desired is an intake rack system that combines the advantages ofexisting metal and plastic rack systems. What is desired, in particular,is an apparatus and method for bringing the advantages of plastic intakerack systems to existing metal rack system installations in aninexpensive manner that does not require removal, replacement, orreinstallation of the existing metal rack systems.

SUMMARY OF THE INVENTION

The present invention provides a protective sleeve for the verticalmetal bars forming the blades of a metal intake or trash rack system. Aprotective sleeve in accordance with the present invention is made of aplastic material, is easily attached to the blades of an existing metalrack system without removing the existing system, and imparts toexisting metal rack system many of the advantages of plastic intake racksystems. A protective sleeve in accordance with the presenting inventionmay be used on the metal bars or blades of intake racks and othersimilar structures used for screening debris from water intakespositioned in natural or man-made exposed above-ground water sources. Aprotective sleeve for bar racks in accordance with the present inventionmay be used in combination with various different water intake screeningsystems such as trash racks, intake screens, cooling water screens,storm water overflows, culvert and drainage underflows, headworks, andflow straighteners, as used in applications such as hydroelectric andother power plants, cooling towers for nuclear energy and other powerplants and other facilities, pulp and paper mills, steel mills,petro-chemical plants, municipal water and/or waste water plants, fishdiversions, other water filtering and/or screening facilities orsystems, etc.

A protective sleeve in accordance with the present invention may bemanufactured using a conventional extrusion process from a plasticmaterial such as HDPE. A protective sleeve in accordance with thepresent invention may be manufactured in this manner to any desiredlength and other dimensions so as to fit over the metal bar blades ofexisting and future metal intake rack systems. Protective sleeves inaccordance with the present invention preferably are designed to snap inplace over the metal bars of conventional metal rack systems and toprovide a positive and secure fit when in place. Protective sleeves inaccordance with the present invention are thus easily replaceable whenneeded.

Further objects, features, and advantages of the invention will beapparent from the following detailed description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 perspective view in detail of a portion of a known plastic intakerack system.

FIG. 2 is a perspective view of a larger portion of an intake racksystem having metal blades unto which protective sleeves in accordancewith the present invention may be mounted.

FIG. 3 is a leading edge view of a portion of an exemplary protectivesleeve in accordance with the present invention as mounted on a portionof a metal intake rack blade.

FIG. 4 is a cross sectional view of the exemplary protective sleeve inaccordance with the present invention and metal intake rack blade astaken along the line 4-4 of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a protective sleeve for use with themetal blades of intake racks, an intake rack system employing suchprotective sleeves, and a method of employing such protective sleeveswith existing in-place metal intake racks to provide the benefits of anon-metallic rack without requiring replacement of the metal rack.Protective sleeves in accordance with the present invention may be usedwith intake racks as well as other similar systems and structures. Forexample, protective sleeves in accordance with the present invention maybe used with a variety of metal intake screens, cooling water screens,storm water overflow screening structures, culvert and drainageunderflow screening structures, headworks, and flow straighteners, etc.Such intake racks and similar structures may used in association withhydroelectric or other power plants, intake ducts for nuclear energy orother facility cooling water, pulp and paper mills, steel mills,petrochemical plants, municipal water and/or waste water treatmentplants, fish diversions, and other water filtering or screeningfacilities or systems, etc. Such systems and facilities may be locatedin any natural or man-made exposed above-ground water source, such asrivers, lakes, oceans, reservoirs, irrigation and flood water canals,water parks, and other water conveyance structures, etc. in which anyvariety or type of natural or man-made debris may be found that is to bescreened by the intake rack screening system or structure.

As illustrated in FIGS. 1 and 2, a typical intake trash rack 12 isformed of a series of spaced apart blades 14. The vertical blades 14 aremounted on horizontal support structures 16, such as horizontal rods orsimilar structures. Spacers 18, typically also mounted on the verticalsupport structures 16, proved the desired separation between the blades14. The vertical blades 14 and horizontal support structures 16 may bemounted together in an appropriate frame 19 to form the complete trashrack structure 12. (For example, the ends of the horizontal supportstructures 16 may be bolted as otherwise secured to the frame 19.

A portion of a trash intake rack 12 made of a plastic material asillustrated in FIG. 1. Such an intake rack 12 may have blades 14 and 18made of various plastic materials using various manufacturing processes.For example, such an intake rack may have blades and spacers made ofextruded HDPE or some other material or by some other processes. Thehorizontal support structures 16 upon which the blades 14 and spacers 18are mounted may similarly be made of a plastic (e.g. solid pultrudedFPR) or another appropriate material. The leading and trailing edges ofthe rack blades 14 may be curved or flat. As discussed above, suchcurved edges facilitate water flow through the rack 12 as well as reducethe effect required to clear debris from the rack 12. As discussedabove, plastic intake racks 12 of the type illustrated in FIG. 1 havemany advantages including no corrosion, resistance to ice build up,light weight, and resistance to fowling by marine life. Plastic racks 12of the type illustrated in FIG. 1 are available, for example, from HydroComponent Systems LLC of Watertown, Wis.

A conventional trash intake rack 12 having metal (e.g., steel) blades 14is illustrated in FIG. 2. In this case, and as is typical, the rackblades 14 are generally bar shaped, i.e., the blades 14 are generallyrectangular in cross section. (The terms “rack blades”, “rack bars,” andsimilar terms are used interchangeably herein as well as in theaccompanying claims.) Although providing a high strength trash intakerack 12, a trash intake rack 12 having metal bar blades 14 has severallimitations, as discussed above.

In operation, the intake trash rack 12 is positioned such that theparallel blades 14 extend downward substantially vertically into a watersource, e.g., a river. A water intake, e.g., for a hydroelectric plantor other system or facility, is positioned approximately directlybehind, e.g., downstream from, the intake rack 12. Thus, water flowingdownstream is allowed to enter the water intake through the spacesformed between the vertical blades 14 forming the intake rack 12. (Notethat additional finer screening of debris also may be provided betweenthe intake rack 12 and the system or facility water intake.) Natural orman-made debris flowing downstream, however, is prevented from enteringthe water intake by the blades 14 of the intake rack 12. Such debriscaptured by the intake rack 12 will tend to accumulate on the surface ofthe rack 12, typically at or slightly below the water line, and can beremoved therefrom using a variety of different systems and methods, suchas using the Trash Rake System for Clearing Intake Racks and the Likedescribed in U.S. patent application Ser. No. 11/144,393, filed on Jun.3, 2005.

A protective sleeve 20 in accordance with the present invention, asmounted on a metal intake rack blade 14, is illustrated in, and will bedescribed in detail with reference to, FIGS. 3 and 4. The metal rackblade 14 may be made, for example, of cold rolled steel, or some othersimilar metallic material and has for example, a rectangular crosssectional shape, and may be of almost any desired length appropriate forthe intake rack system 12 in which the blade 14 is used.

An exemplary protective sleeve 20 in accordance with the presentinvention has four sides that preferably completely or substantiallysurround the metal intake rack blade 14 when positioned thereon. Thefour sides include a leading side 22, two elongated side walls 24 and26, and a trailing side 28.

The leading side 22 of the protective sleeve 20 is that side thereofagainst which water will flow and debris will accumulate when the sleeveis in use in position an intake rack blade 14. The leading side 22 ofthe protective sleeve 20 preferably may be made of thicker materialthan, for example, the side walls 24 and 26 of the sleeve 20. Thus, theleading side 22 of the sleeve 20 is better able to withstand the impactof debris and incidental contact thereon. The outer surface of theleading side 22 of the sleeve 20 preferably may be curved to provide aradiused leading edge to the intake rack blade 14 when mounted inposition thereon

The side walls 24 and 26 extend backward in the same direction from theleading side 22 of the protective sleeve 20. The side walls 24 and 26 ofthe sleeve preferably may be made of the same material as the leadingside 22, but are thinner, such that the side walls 24 and 26 aresomewhat flexible.

The trailing side 28 of the protective sleeve 20 preferably is formed tohave a structure that facilitates mounting the sleeve on an intake rackbar blade 14 such that the blade 14 is surrounded by the sleeve 20. Forexample, the trailing side 28 of the sleeve may include a projectionformed extending from one of the side walls 24 for a sufficient distanceto contact the other side wall 26. The projection is angled on the outersurface thereof to facilitate mounting of the sleeve 20 on the rackblade 14.

A protective sleeve in accordance with the present invention may be madeof a plastic material such as HDPE, although other appropriate durableplastic materials also may be employed. The protective sleeve may bemanufactured using an extrusion process or any other appropriate processin any desired length appropriate for the intake rack system in whichthe protective sleeves will be used. The dimensions of the leading side22, side walls 24 and 26, and trailing side 28 of the sleeve 20 may beselected such that the size and shape of the interior of the sleeve 20corresponds to the intake rack blade 14 to be covered thereby such thatthe sleeve 20 surrounds the blade 14 and makes a positive and secure fittherewith when mounted thereon.

It should be understood that the present invention is not limited to theparticular exemplary applications and embodiments illustrated anddescribed herein.

1. A protective sleeve configured and dimensioned to protect an intakerack bar configured to allow fluid flow therepast, the protective sleevecomprising: a leading side coupled to a first side wall and a secondside wall; and a trailing side coupled to one of the first and secondside walls; the leading side, trailing side, and first and second sidewalls defining an interior space configured to receive an intake rackbar; the protective sleeve being configured such that when it is in aninstalled configuration, the interior space extends in a first directionperpendicular to the direction of fluid flow and in a second directionparallel to the direction of fluid flow, with the interior spaceextending farther in the first direction than in the second direction;said trailing side being selectively displaceable between a firstconfiguration, in which the sleeve is configured to receive the intakerack bar and a second configuration, in which the sleeve is configuredto substantially surround a portion of the intake rack bar and allowfluid flow.
 2. The protective sleeve of claim 1, wherein the protectivesleeve is composed of high density polyethylene.
 3. The protectivesleeve of claim 1, wherein the leading side of the protective sleeve isradially thicker than at least one of the first side wall, the secondside wall, and the trailing side.
 4. The protective sleeve of claim 1,wherein the leading side of the protective sleeve is configured toextend along the rack bar perpendicular to the direction of fluid flow;and wherein the first and second side walls each extend from the leadingside parallel to the direction of fluid flow.
 5. The protective sleeveof claim 1 wherein in the second configuration the trailing side extendsperpendicularly from the one of the first or second side walls towardsthe other of the first and second sides such that the inner spacedefined by the leading side, the first and second side walls, and thetrailing side is generally rectangular.
 6. A method of protecting anintake rack bar having a plurality of metal blades, without replacingthe metal blades or intake rack bar, from at least one of ice build up,corrosion, and fouling by marine life, the method comprising the stepsof: providing a non-metal protective sleeve configured to surround andprotect at least one of the metal blades of the intake rack bar; andmounting said non-metal protective sleeve on at least one of the metalblades.
 7. The method of claim 6, wherein said at least one metal bladehas a leading side, first and second side walls extending from theleading side, and a trailing side and extends axially perpendicular tothe leading side and the trailing side, and wherein said protectivesleeve substantially surrounds the leading side, first and second sidewalls, and the trailing side, and wherein said protective sleeve extendsover an axial portion of said at least one metal blade.
 8. The method ofclaim 6, wherein said at least one metal blade defines a rectangularcross sectional shape.
 9. The method of claim 6, wherein a portion ofsaid sleeve configured to extend over said leading side is thicker thana portion of said sleeve configured to extend over at least one of saidfirst side, said second side, and said trailing side.
 10. The method ofclaim 6, wherein said sleeve comprises high density polyethylene.